The Canadians are very serious at the border if you have a DUI on your record. You need to bring proof of your atonement such as proof that you did community service and took an ARD course, etc. etc...
My company has an office in Canada, and we send people back and forth from the USA to Canada and reverse.
At the end of the day, any border agent can deny you access at their own discretion.
If they don't like your attitude, they just deny you access.
So what's the answer....have all of your paperwork and be very, very nice.
